#!/usr/bin/python3
'''youyongchi wenti'''

PI = 3.1416

class Circle
    '''yuan'''
    def __init__(self,radius)
        self.radius = radius

    @property
    def perimeter(self):
        '''zhouchang'''
        return 2*PI*self.radius

    @property
    def area(self)
        '''mianji'''
        return PI * (self.radius ** 2)

def main():
'''zhuhanshu'''
